Container and electrical heater means



June 6, 1964 A. R. WELLS ETAL CONTAINER AND ELECTRICAL HEATER MEANS 2Sheets-Sheet 1 Filed Oct. 25, 1962 7 W F E 2 a? z J w 4 6 0 Jvv W m 3, uE m 2 i W If N w a,

ENTORS N R.WEI LS BY ROBERT M. WELLS INV ALTO

ATT YS.

June 16, 1964 LLS ETAL- 3,137,786

CONTAINER AND ELECTRICAL HEATER MEANS Filed Oct. 25, 1962 2 Sheets-Sheet2 (9C 4/ W E 4? INVENTORS ALTON R.WELI S By ROBERT M.WELLS AT T YS.

United States Patent M 3,137,786 CONTAINER AND ELECTRICAL HEATER MEANSAlton R. Wells, 4573 W. Tradewinds Ave., Lauderdaleby-the-Sea, Fla, andRobert M. Wells, 4371 Ira Road, Akron- 13,0l'1io Filed Oct. 25, 1962,Set. No. 2'32',019 12 Claims; (Cl. 219-441) The presentinvention-relates to an improved container and electrical heatermeanstherefor, and especially to a container that is adapted to be madefrom a suitable plastic material and which has anelectrical resistanceheater and electrical'circuit control means associated therewith.

The present invention particularly relates to containers such as areused as percolators, for coflee brewing, and similar heating actions.These previous types of containers of this type have been made frommetal, and have been relatively expensive. With competitive conditionsin the industry, it is quite important that the cost of these containersand control means therefor, if possible, be reduced; if a satisfactorytype of an attractive, durable container and electric heater and controlmeans therefor can be provided.

The present invention has as its general object the provision of a noveland improved container unit of the type described and characterized bythe use of one metal positioning plate at a base portion of thecontainer for pcsitioning a heater unit therein, whichplate is securedto the container by an integral retaining flange formed therein.

Another object of the invention is to provide a container of the classdescribed where the container can be made from any suitable plasticmaterial, either thermo plastic or thermosetting, and where a stainlesssteel positioning plate, or other metal plate having low heatconductivity is provided in the container.

Another object of the invention is to use an integral double walledannular flange of a metal support plate in a plastic container to securethe plate to a hole or opening provided in the bottom portion of thecontainer to seal the opening in the container and to use the metalsupport plate for securing heater means carried thereby in thecontainer.

A further object of the invention is to complete a plastic containerhaving an open lower end with a metal base plate-that blends into thecontour of the sides of the container and is secured to the open lowerend of the container by an integral section of the base plate.

A further object of the invention is to provide a special combinationbetween a metal base plate, an electric heater, a heater circuitcontrol, and a plastic container, whereby a' novel and attractive butdurable construction is provided, which construction is sturdy andrelatively economical, and has desirable operating characteristics.

The foregoing and other objects and advantages of the invention will bemade more apparent as the specification proceeds.

Attention now is particularly directed to the accompanying drawings,where:

FIG. 1 is a fragmentary vertical section, with the heater means shown inelevation, of a combined container, elec* trical heater means andcontrol embodying the principles of the invention;

FIG. 2 is a fragmentary vertical section of a modified container unit ofthe invention;

FIG. 3 is a fragmentary vertical section of a further modification ofthe container and associated means as shown in FIG. 1;

FIG. 4- is a fragmentary vertical section of a further modification ofthe novel container unit and associated r 3,137,786 Patented June 16,1964 means of the invention with the metal base plate extending up andforming a portion of the sides of the container;

FIG. 5 isa fragmentary vertical section of amodified container unit ofthe invention illustrating a modified construction of a metal supportplate; and

FIG. 6 is a fragmentary vertical section of afurther modified embodimentof the invention.

When referring to corresponding members shown in the drawingsandreferred to in the'specification, corresponding numerals are usedto-facilitate comparison therebetween.

Generally speaking, the present invention, as one important embodimentthereof, relatesto-the combination of a substantially rigid, hollow,molded plastic liquid receiving body having a side wall terminating in abottom opening; ametal plate of greater size than the opening in theplastic body; means for securing the metal plate to the plastic bodycomprising an interlocked connection between peripheral portions on themetal plate and a peripheral portion of the plastic body surrounding theopening to seal the opening and directly secure the metal plate to theplastic body; an electric heater secured to a center portion of themetal plate in sealed relation thereto, the interlocked connection beingradially spaced from the electric tion being of an area correlated withthe wattage of the electric heater, the size of the metal plate and thematerial from which it is made, and the composition of the plastic bodyso as to prevent the transfer of excessive heat to the plastic bodythereby preventing damage to the plastic body by any use thereof, saidmetal plate being in contact with the liquid in said plastic body; athermostat positioned below the metal plate in operatively direct heatexchange relation thereto to be primarily controlled by the temperaturethereof in normal operation of the appliance; circuit means connectingto the thermostat and electric heater and being connectable to a powersupply; and base means for the plastic body operatively secured thereto.

Attention now is particularly directed to the detailsof the structureshown in the accompanying drawings, and a container is indicated as awhole by the numeral 1 in FIG. 1 of the drawings. This container 1 canbe made of any suitable size and shape, and is made from a suitablethermoplastic material such as high density polyethylene, or athermosetting plastic material, such as melamine.

The container 1 is shown as having a side wall terminating in asubstantially flat base or bottom 2 with an aperture or opening 3 beingformed in the bottom 2. A conventional electrical heater 4 of anysuitable known construction is operatively positioned within thecontainer 1 and such heater has a resistance coil provided therein; Theheater 4 includes a metal enclosure, or can 5 which has a base flange orrib 6 formed at or adjacent to the base of this can 5 by suitable means.A stud 7 is suitably secured to the heater, mm the can 5 and extendsaxially downwardly therefrom.

In order to position the heater 4 within the container 1, but yet tothermally isolate and insulate such heater from the plastic materialusually u'sed'to, form the container 1, a generally fiat metal plate 8is Provided and the upper surface of the metal plate 8 adjacent acentral aperture therein by conventional Welding techniques, asindicated at 9.

It is an important feature of the invention that this metal plate 8 issecured or sealed in engagement with the aperture 3 provided in thebottom of the container 1, and to achieve this seal in the presentinvention, an integral, double walled annular flange is formed in themetal plate 8 adjacent but spaced radially from the periphery thereof.Initially this flange 10 would be formed to extend axially of thecontainer 1, as indicated in dotted lines in FIG. 1, and the flange 10is of a diameter to be r'e- 'ceived snugly in the aperture 3. Suitablesealing cements and/or sealing gaskets indicated at 11 and 12 areprovided on the upper surface of the container bottom 2 and on the lowersurface thereof, respectively. These gaskets can be made from glassfibers or other suitable material. It is within the concept of theinvention to reinforce the plastic container 1 with suitable material,such as glass fibers, adjacent the margins of the aperture 3.

After the metal plate has been assembled in the container 1, thensuitable means are brought into engagement with the flange 1t and theupper surface of the metal plate 8 so as to spin, shape, or fold overthe flange 10 to cause it to extend radially outwardly in the assemblyand to provide an overhanging portion 13 therein extending generallyparallelto the bottom 2 of the container. Such overhanging portion 13compresses the container bottom 2 immediately adjacent the aperture 3between the generally planar portion of the metal plate 8 and theoverhanging portion 13 of theflange 10 whereby an eifective, fluid tightseal is provided between the container and the metal plate to form thedesired enclosure for heating action. It will be noted that the marginsof the metal plate 8 extend radially beyond the outermost portion of theradially overhanging portion 13 of the flange 10 to distribute thecompression stresses applied to the bottom of the container.

In order to complete the container 1 for use, a suitable electrical heatcontrol member, such as a conventional thermostat 14-, is operativelyassociated with the lower surface of the metal plate 8, and usually ingood heat conductive engagement with both the metal plate and the can 5of the heater 4. A metal clamp arm 15 is secured to the stud 7 andengages the thermostat 14 to position it in the specified manner. A nut16 engages the stud 7 to secure the clamp arm and thermostat inoperative association with the plate and heater can.

The electrical control circuit for the heater 4 is completed by means ofpower supply leads 17 and 18 that connect to conventional terminalprongs provided in a base 19 for the container 1. These leads connect tothe thermostat 14 and to the heater, respectively, and a lead 20 extendsfrom the thermostat to the heater to connect the thermostat and heaterin a series circuit for control of the heating action in the container 1by the thermostat 14-. Obviously the thermostat 14 is calibrated in sucha manner as to prevent excessive heating of the container 1, or itscontents.

The base 19 for the container 1 is secured thereto, as by a positioningplate 21 afiixed to the stud 7 by a lock nut 22.

FIG. 2 of the drawings shows a modified container 1a of the inventionwhich has a metal support plate 8:; provided therein, as in the otherembodiment of the invention. However, in this instance, a metal washer23 is provided intermediate an overhanging portion 13a of a flange 10aof the metal plate and the adjacent surface of the container 1a. Suchmetal washer 23 has a cylindrical portion, or flange 24 that extendsaxially of the aperture formed in the bottom of this container 1a to apoint immediately adjacent the sealing material, or gasket 11a carriedby the upper surface of the bottom portion of the container 1a. Hence,the cylindrical portion 24 limits the compression of the container 1abetween the overhanging portion 13a of the flange 10a and the remainderof the support plate 8a, but yet a desired compressive sealingengagement is obtained between the bottom portion of this container andthe support plate 8a.

A further modified container 1b is shown in FIG. 3 of the drawings. Inthis instance, an electric heater 4b is provided where a metal can 55thereof has a metal plate 8b formed integrally with the metal can 5bwhereby the separate assembly of the electric heater to the metal support plate is avoided. Again, a positioning stud 7b extends from theheater 4b to position other members in operative association with thecan 5b in this embodiment of the invention. Preferably this supportplate 8b and can 5]) would be formed from a low heat conductivematerial, such as stainless steel, and the support plate is secured tothe container as previously described.

A further modification of the invention is shown in FIG. 4 where in thisinstance a larger aperture or opening is provided in the base portion ofthe container. Thus a container 10 is shown that has an open lower endor aperture 30 formed in the side walls of the container. A metalsupport plate So has an electric heater 4c suitably secured thereto andin this instance the metal plate is of cup shape and has a verticallyupwardly extending marginal portion 4% provided thereon. This marginalportion 40 of the metal plate 8c is contoured complementary in size tothe lower end of the container 10 and it has an annular flange providedin the marginal portion 40 and initially extending radially inwardly ofthe metal plate and container assembly. After the container 10 and themetal plate 8c have been brought into operative association, the flange10c is folded or turned to provide an overhanging portion 13c forsecuring the lower margins of the side walls of the container to themetal plate to complete the enclosure. The container 10, when completed,has a sealed joint between an integral, vertically extending flange 100having a pair of spaced walls therein between which the lower open endof the container 1c is received.

Any suitable base 41 is provided for the container 1c and suitablysecured thereto as by a lock nut 42 engaging the heater stud.

Attention now is particularly directed to the details of the modifiedimproved container and electrical heater means of the invention as shownin FIG. 5. In this instance, a suitable plastic container 1d is shownthat has a side wall terminating in an aperture 3d formed in the base orbottom portion of the container. The container also includes a metalsupport plate 8d that preferably is made from stainless steel or othermaterial of low heat conductivity, and this support plate 8d has aperipheral section 50 which is doubled back upon the support plate 8d.The support plate 8d normally is substantially flat and lies in anddefines a plane with the doubled section 50 including a portion lying inthe plane of the support plate 8d and with another portion, usually thelower portion of this doubled section 50, lying underneath and at leastsubstantially parallel to the plane of the support plate 8d. The doubledsection 50, as initially formed, includes a substantially cylindricalflange 51 which, when assembled in the container 1 in the manner shown,extends downwardly from the plane defined by the support plate 801. Theinitial position of this flange 51 is partially indicated in dottedlines in FIG. 5, and in the ultimate positioning of the metal supportplate 8d and container 1d in assembled relationship, an end section 52of the flange 51 has been suitably rolled, turned, or otherwise bentoutwardly in the container assembly so as to be turned over into goodcompressive engagement with the bottom portion of the container 1d inthe section thereof lying immediately adjacent the aperture 3d. Anysuitable gaskets, or sealing cements or means, such as a gasket 12d, isshown compressed between the end section 52 of the flange and the lowersurface of the container id in its base or bottom section. A furthergasket, or seal means can be associated with the upper surface of thecontainer adjacent the aperture 3d, if desired. This unit of theinvention also includes a removable support or base 19d that is securedto the remainder of the container, as by a lower support plate 21d thatis attached to the plate 8d or means carried thereby in a manner similarto that shown in the other figures of the drawings.

A further modification of the invention, illustrated in FIG. 6,illustrates a suitable plastic container 1e of any desired shape, whichin this instance is shown as having a support base 62 operativelysecured thereto by being formed integrally therewith as a single unit.The container 1e has a bottom 2e, which normally would be substantiallyflat and lie in and define a plane, which base 2e has an aperture 3eformed therein. Again, a metal sup port plate Se is provided forfilling, or sealing the aperture 8e provided in the base or bottom 2e ofthe container and for operatively positioning a suitable heater in thecontainer 1e for heating action. The plate 86, formed from low heatconductivity material, is originally provided with an integraldownwardly extending cylindrical flange 60 that is adjacent but spacedradially from the margins of the support plate 8e, as indicated in thedrawings. Such downwardly extending flange 60 has a flange end 61 formedthereon that is suitably rolled, turned, spun, or folded outwardly inthe container unit 1e to take the position illustrated in the drawings.In such position, the flange end 61 is formed to have good compressiveengagement of the portion of the container bottom 22 immediatelyadjacent the aperture 3e. Any suitable gaskets He and 12a are shown inassociation with the adjacent surfaces of the support plate 8e and theflange end 61. It may be desired to provide a metal spacer ring, orwasher 23c, that has a cylindrical portion or flange 24e formed thereonand extending axially of the aperture 3e, between the plate 8e and theflange end 61 to prevent undesirable compression of the container bottom2e.

In providing improved container and electrical heater means inaccordance with the principles of the invention, any suitable type ofcontrol circuits may beprovided for this electrical heater. Thus anyknown type of thermostats, fuses, and equivalent means may be used inthe electrical control circuit. Such thermostats and/or fuses, orequivalent members would be positioned in good heat conductive contactwith at least the metal support plates used in the containers. Thethermostats used preferably are of the periodic, or pulsing swing type,principle. Thus, such thermostats would be designed, for example, to cutoff at 185 F. after coffee has been brewed in the container, and thensuch thermostats would pulse on and off repetitively and would maintaina steady or holding temperature, such as about 185 F. thereafter, forthe contents of the container, by the use of heaters of knownconstruction and usually having two separate heating coils therein, oneof relatively low Wattage for the heat maintenance action alone. Thethermostats also function as safety devices to cut off current to theheater in the event that power is supplied to the heater in thecontainer and the container runs dry, or is coupled to a power circuitaccidentially with no liquid contents being provided in the container.

It will be realized that the support plates 8 or equivalent provided inthe container of the invention may in any desired instance have theheaters used in association therewith either fixedly connected thereto,or with the support plate being formed integrally with the heater can,specifically as shown in FIG. 3 hereof. Thesupport plates 8, orequivalent members in the otherembodiments of the invention, form heatbarrier plates in the container units of the invention. Likewise, thespacer gaskets or rings equivalent to the members 23 and 23e disclosedherein can be used in any embodiment of the invention, as desired. FIGS.1 and 2 well illustrate 110w the flange means provided for securing thesupport plates to the container can extend in either direction from thegeneral plane of the support plates, so as to engage the container andform the desired enclosure therewith. Likewise, the securing flange, asshown in FIG. 4, may be provided both on the inner surface of thecontainer, as shown, or the flange, in this instance, could be a singlewalled thickness flange, as shown in FIGS. 5 and 6, for engaging thecontainer to secure the metal support plate thereto.

Any suitable sealing means and/ or adhesives or cements may be used atany of the connections of metal to metal, or plastic to metal in thecontainers of the invention.

It should be noted that in some instances it may be necessary to makethe metal support plates of the invention from conventional metallicmaterials, such as aluminum, which do not have the desired low rate ofheat conductivity, as does the stainless steel and equivalent materials.However, some benefits from the invention still can be realized from theconstruction of the invention even without the desirable low heatconductivity in the metal support plate. Additional, or thicker gasketmeans might be required to help insulate the metal support plate fromthe plastic container in such instances, or the plastic container may bemade from more heat resistant material to provide a useful, desirablestructure.

It also should be noted that the electric heater means used in the unitsof the invention may not have a support stud extending downwardlytherefrom, as electric heaters have been made with a threaded baseportion upon the metal enclosure for the heater at the lower endthereof, and then the electric heater, for example, couldbe secured to ametal support plate by a lock nut engaging the threaded lower end of thecan. The can of the heater would have an annular flange thereon at theupper end of this threaded section on the can to be drawn against theupper surface of the support plate to aid in securing the can inposition. The invention contemplates use of any type of electric heatersin the containers of the invention. If a downwardly extending stud isprovided on the heater, it can be secured to the heater enclosure, orcan' in any known manner.

The various rolling, turning, folding, spinning, or shaping actionsdisclosed for engaging a portion of the flange or channel of the metalplates with the containers can be generally referred to as metal formingaction.

It will be obvious that the area ofthe continuous portion of the metalplate spacing the heater unit from the channel section of the metalplate and hence from the plastic container is notof a particular sizebut that such area depends upon the wattage of the heater, the materialfrom which the plate is made, and the composition of the plasticcontainer so as to provide the desired thermal barrier action in themetal plate.

It will be realized that the container of the invention can be used forany desired heating action, such as for brewing coffee, or for makingtea, chocolate, oi the like. The thermostats provided in the containersprovide a very effective safety control means therein whereby excessiveheating of the container and its contents are avoided, even though thepower be supplied to the container, inadvertently, when the container isempty.

The terms vertically and horizontally, when used in the specificationand claims are used for reference only, and the container is assumed tobe positioned on a vertical axis for such designation of directions.

It also will be realized that any suitable type of a base may be used onthe containers of the invention,- and may even be omitted in someinstances.

The flange means on the metal plate or disc 8, or equivalent means inthe containers of the invention, form groove means to engage tongueportions of the plastic container.

The containers of the invention can be made of any suitable size andshape by any known molding or shaping process, and the components of thebase portions thereof can be assembled thereinto from the bottom, ortop, as is preferred. The containers will be very attractive in designand will have a lengthy service life. Hence it is believed that theobjects of the invention have been achieved.

While several complete embodiments of the invention have been disclosedherein, it will be appreciated that modification of these particularembodiments of the invention may be resorted to without departing fromthe scope of the invention as defined in the appended claims.

What is claimed is:

1. In combination in a portable electric appliance,

a substantially rigid plastic container having a side wall terminatingin a bottom aperture,

an electrical heater unit,

a metal plate of greater size than said aperture having a continuousperipheral channel section of generally U-shape cross section providedthereon, said heater unit being secured to a center portion of saidmetal plate in sealed engagement therewith, said channel section beingradially spaced from said heater unit by a continuous intermediateportion of said metal plate,

said metal plate being secured to said plastic container to close saidaperture by a portion of said plastic container wall surrounding saidaperture that is compressively secured between opposed walls of saidchannel section by a metal forming operation on at least one of thewalls defining said channel section to seal said aperture and positionsaid heater unit within but spacially and thermally insulated from saidplastic container by said continuous portion of said metal plate, saidcontinuous portion being of an area correlated with the wattage of saidheater unit, the size of said metal plate and the material from which itis made, and the composition of said plastic container so as to preventthe transfer of excessive heat to said plastic container therebypreventing damage to said plastic container by any use thereof; saidmetal plate being in contact with the liquid in said container,

a thermostat positioned below and in substantially direct heat exchangerelation to said metal plate to be primarily controlled by thetemperature of said metal plate in normal operation of the appliance,

circuit means connecting to said thermostat and said heater unit andbeing connectable to a power supply, and

base means for said plastic container operatively se cured thereto.

2. In combination in an electric liquid heating appliance,

a substantially rigid thermoplastic plastic container having a side Wallterminating in a bottom aperture,

an electrical heater unit,

a metal plate of greater size than said aperture having a continuousperipheral channel section of generally U-shape cross section providedthereon, said heater unit being secured to a center portion of saidmetal plate in sealed engagement therewith, said channel section beingradially spaced from said heater unit by a continuous intermediateportion of said metal plate,

said metal plate being secured to said plastic container to close saidaperture by a portion of said plastic container wall surrounding saidaperture that is compressively secured between opposed walls of saidchannel section by a metal forming operation on at least one of thewalls defining said channel section to seal said aperture and positionsaid heater unit within but spacially and thermally insulated from saidplastic container by said continuous portion of said metal plate, saidcontinuous portion being of an area correlated with the wattage of saidheater unit, the size of said metal plate and the material from which itis made, and the composition of said plastic container so as to preventthe transfer of excessive heat to said plastic container therebypreventing damage to said plastic container by any use thereof; any partof said portion of said plastic container that is softened by excessiveor abnormal heat fiow thereto from said metal plate resolidifying insitu when heat flow thereto terminates; said metal plate being incontact with the liquid in said container,

a thermostat positioned below said metal plate and in operatively directheat exchange relation to said metal plate to be primarily controlled bythe temperature of said metal plate in normal operation of theappliance,

circuit means connecting to said thermostat and said heater unit andbeing connectable to a power supply, and

base means for said plastic container operatively secured thereto.

3. In combination in a portable electric appliance,

a substantially rigid plastic container having a side wall terminatingin a bottom aperture,

an electrical heater means,

a metal plate of greater size than said aperture having a continuousgenerally horizontally positioned radially outwardly open peripheralchannel section of generally U-shape cross section formed therein andhaving an offset center portion, said heater means being operativelyassociated with said offset portion of said metal plate and in heatexchange relation therewith, said channel section being radially spacedfrom said heater means by a continuous intermediate portion of saidmetal plate,

said metal plate being secured to said plastic container to close saidaperture by a portion of said plastic container wall surrounding saidaperture that is compressively secured between opposed Walls of saidchannel section by a metal forming operation on at least one of thewalls defining said channel section to seal said aperture and positionsaid heater means within but spacially and thermally insulated from saidplastic container by said continuous portion of said metal plate, saidcontinuous portion being of an area correlated with the wattage of saidheater means, the size of said metal plate and the material from whichit is made, and the composition of said plastic container so as toprevent the transfer of excessive heat to said plastic container therebypreventing damage to said plastic container by any use thereof; saidmetal plate being in contact with the liquid in said container,

a thermostat positioned below said metal plate and in operatively directheat exchange relation to said metal plate to be primarily controlled bythe temperature of said metal plate in normal operation of theappliance,

circuit means connecting to said thermostat and said heater means andbeing connectable to a power supply, and

base means for said plastic container operatively secured thereto.

4. In combination in a portable electric appliance,

a substantially rigid plastic container having a bottom openingextending over a substantial portion thereof,

an electrical heater means,

a metal plate of greater size than said aperture having a continuousperipheral flange formed therein, said flange being spaced radiallyinwardly a short distance from the periphery of said plate and beingconnected to said plate by a doubled back edge section formed on saidplate, said flange having a first portion extending substantiallyvertically for a distance and a second portion extending substantiallyradially outwardly, said first and second portions and said edge sectiondefining a channel, said metal plate being secured to said container toclose said opening by a portion of said container surrounding saidopening being compressively engaged in said channel between said doubledback edge section and said second portion by a metal forming operationon said second portion, said heater means being secured to a centerportion of said metal plate in sealed engagement therewith, said flangebeing radially spaced from said heater means by a continuous portion ofsaid metal plate,

said metal plate sealing said aperture and positioning said heater meanswithin but spacially and thermally insulated from said plastic containerby said continuous portion of said metal plate, said continuous portionbeing of an area correlated with the wattage of said heater means, thesize of said metal plate and the material from which it is made, and thecomposition of said plastic container so as to prevent the transfer ofexcessive heat to said plastic container thereby preventing damage tosaid plastic container by any use thereof; said metal plate being incontact with liquid in said container and being made from a materialhaving a low rate of heat conductivity,

a thermostat positioned below said metal plate and in operatively directheat exchange relation to said metal plate to be primarily controlled bythe temperature of said metal plate in normal operation of theappliance,

circuit means connecting to said thermostat and said heater means andbeing connectable to a power supp y and base means for said plasticcontainer operatively sesecured thereto.

5. In combination in a portable electric appliance,

a substantially rigid plastic container having an opening extending overa portion of the bottomarea thereof,

an electrical heater means,

a peripherally flanged metal plate of greater size than said aperture,said flange being continuous and at least having portions spacedradially inwardly a short distance from the periphery of said plate,said flange having a first portion extending substantially verticallyfor a distance and a second portion extending radially outwardly, saidportions together with adjacent parts of said plate defining a channel,said metal plate being secured to said container to close said openingby means of the portion of said container surrounding said opening beingcompressively engaged in said channel by a metal forming operation onsaid second portion of said flange, said heater means being secured to acenter portion of said metal plate in sealed engagement therewith, saidflange being radially spaced from said heater means by a continuousportion of said metal plate, said second portion of said flangeextending vertically when said plastic container and metal plate areinitially assembled and being engaged with said plastic container by ametal, forming operation on said second portion,

said metal plate sealing said aperture and positioning said heater meanswithin but thermally insulated from said plastic container by saidcontinuous portion of said metal plate, said continuous portion being ofan area correlated with the wattage of said heater unit, the size ofsaid metal plate and the material from which it is made, and thecomposition of said plastic container so as to prevent the transfer ofexcessive eat to said plastic container thereby preventing damage tosaid plastic container by any use thereof; said metal plate being incontact with liquid in said container,

a thermostat positioned in substantially direct heat eX- change relationto said metal plate and said heater means to be primarily controlled bythe temperatures thereof,

circuit means connecting to said thermostat and said 10 heater means andbeing connectable to a power supply, and

base means for said plastic container operatively secured thereto.

6. In combination in a portable electric appliance,

a substantially rigid plastic container having a bottom section with anaperture therein,

an electrical heater means,

a metal plate of greater size than said aperture having a continuousperipheral channel section of generally U-shape cross section providedthereon and being substantially horizontally positioned with a radiallyfacing initially open channel mouth, said heater means being operativelysecured to a center portion of said metal plate, said channel sectionbeing radially spaced from said heater unit by a continuous intermediateportion of said metal plate,

said metal plate being secured to said plastic container to close saidaperture by a portion of said plastic container surrounding saidaperture that is directly and compressively secured between opposedWalls of said channel section by a metal forming operation on at leastone of the walls defining said channel section to seal said aperture andposition said heater means within but spacially and thermally insulatedfrom said plastic container by said continuous portion of said metalplate, said continuous portion being of an area correlated with thewattage of said heater unit, the size of said metal plate and thematerial from which it is made, and the composition of said plasticcontainer so as to prevent the transfer of excessive heat to saidplastic container thereby preventing damage to said plastic container byany use thereof; said metal plate being in contact with the liquid insaid container.

a thermostat positioned below said metal plate and in substantiallydirect heat exchange relation to said metal plate to be controlled atleast in part by heat supply therefrom in normal operation of theappliance,

circuit means connecting to said thermostat and said heater means andbeing connectable to a power sup- P y, and

base means for said plastic container operatively secured thereto.

7. In combination in an electric liquid heating appliance,

a substantially rigid plastic container having a bottom wall with anaperture therein,

an electrical heater unit,

a metal plate of greater size than said aperture having a continuousperipheral channel section of generally U-shape cross section formedtherein which channel section is generally horizontally positioned andhas a radially outwardly facing open mouth, said heater unit beingsecured to a center portion of said metal plate in sealed engagementtherewith, said channel section being radially spaced from said heaterunit by a continuous portion of said metal plate,

said metal plate being secured to said plastic container to close saidaperture by a portion of said plastic container surrounding the aperturethat is compressively secured between opposed walls of said channelsection by a metal forming operation on at least one of the wallsdefining said channel section to seal said aperture and position saidheater unit within but spacially and thermally insulated from saidplastic container by said continuous portion of said metal plate, saidcontinuous portion being of an area cor related with the wattage of saidheater unit, the size of said metal plate and the material from which itis made, and the composition of said plastic container so as to preventthe transfer of excessive heat to said plastic container therebypreventing damage to said plastic container by any use thereof; saidmetal plate tainer surrounding said aperture that is compressivebeing incontact with the liquid in said container, ly secured between opposedwalls of said channel a thermostat positioned below said metal plate andin section to seal said aperture and position said heatoperativelydirect heat exchange relation to said er unit within but spacially andthermally insulated metal plate, from said plastic container by saidcontinuous porcircuit means connecting to said thermostat and said tionof said metal plate, said continuous portion beheater unit and beingconnectable to a power suping of an area correlated with the wattage ofsaid ply, and heater unit, the size of said metal plate and themaintegral plastic base means for said plastic container terial fromwhich it is made, and the composition formed as a unit therewith andextending downwardly of said plastic container so as to prevent thetransfrom said metal plate to support said plastic confer of excessiveheat to said plastic container thereby min r, preventing damage to saidplastic container by any 8. In combination in a portable electricappliance, use thereof; Said wl P a being in C nta t With asubstantially rigid plastic container having a bottom the q i in SaidContainer,

wall terminating in an aperture extending over a a. thermostatpositioned below said metal plate and in ub t ti l portion th f,operatively direct heat exchange relation to said n ele tri l h t means,metal plate to be primarily controlled by the tema metal plate ofgreater size than said aperture having Perahlfe of said metal Plate innormal Operafigh of a continuous double walled peripheral flange formedthe appliance,

therein secured to said container to close said aper- Ci meansConnecting said thermostat and Said ture, said flange being spacedradially inwardly a heater unit and being cohheciahle to a Power pp yshort distance from the periphery of said plate, said and flange havinga fi t Portion extending substantially plastic base means for saidplastic container formed as vertically for a distance and a secondportion exfluhlt therewithtending radially outwardly and compressivelyopera- 10. In combination in a portable electric appliance,

i l engaging and f r i said container bottom a substantially rigidplastic container having a bottom against an adjacent section of saidplate to secure porhoh terminating in a bottom apsflure,

said metal plate to said container bottom Wall, said an elecmcal heatunit,

heater means being secured to a center portion of said a metal Platcmeans of greater SiZB than Said aperture metal plate in sealedengagement therewith, said having cQhthluous, Peripheral, horizontally Pflange being radially spaced from said heater means honed, i y outwardlyP chanhfil Seti0f1 by a continuous intermediate portion of said metalmfians Provided thereon, Said heater unit being seplate, said secondflange portion extending vertically F to a Center Portion of Said talplate means when said plastic Container and metal plate are in sealedengagement therewith, said channel section tially assembled, saidplastic container being commeans 176mg f lly to have a singledownpressively secured between said metal plate and said weirdlyextendl'ng Wan having a Portion Capable of flange by a metal formingoperation on said second being llorlzomally t0 define a Wall of saidchanflange portion to seal said aperture and position said n61 ,Sectlonmeans: Sald Qhahhel i n means being heater unit within but spacially andthermally insurad1a nY spacifd from P heater unlt y a C ntinulated fromsaid plastic container by said continuous 40 mtermedlate Portlcm 0f Saldmetal Plate means, portion of said metal plate, said continuous portionSald melal Plate Int/ans ing secured to said plastic being of an areacorrelated with the wattage of said contillner to Close Said aperture ya Portion of aid heater unit, the Size f said metal plate and theplastic container surrounding said aperture that is terial from which itis made, and the composition of c0mplltissiytily Secured between pp Pti0115 of said plastic container so as to prevent the transfer Saidchannel section means by a metal forming opof excessive heat to saidplastic container thereby eration on said portion of said wall to sealsaid aper- Prevehtihg damage to Said Plastic Container y y time andposition said heater unit Within but spacially use thereof; Said metalPlate being in Contact With and thermally insulated from said plasticcontainer the liquid in h; Container, by said continuous portion of saidmetal plate means, a thermostat hosltlohedvln operahvely dlrechhen saidcontinuous portion being of an area correlated Change relatlon, to Sa1dmetal Plate and Sald heater with the Wattage of said heater unit, thesize of said fii g be Pnmanly Controngd by the temperature metal platemeans and the material from which it is Q made, and the composition ofsaid plastic containercutcigiltteigifialriitsaiczlngggigngoltlomiagdflihgigoggaiteii ipfifisodas 1to prevenhthe transfer of excessive heat to base means for saidplastic container, and i i i thereby Prevemm? dainage means operativelysecuring said base means to said p astlc i i by any t meiill plasticcontainer p ate means being in contact with the llqllld. in said 9. Incombination in a portable electric appliance, plasma contamefrf asubstantially rigid plastic container having a bottom thermostat Saldmetal plate means portion terminating in a bottom aperture and moperatively direct heat exchange relation to an electrical heater unitsaid metal plate means to be controlled at least in a metal plate ofgreater size than said aperture having P y the tehlperatufe of Sflidmetal P1ate means in a continuous peripheral generally horizontallyposinormal opel'atloh 0f the pp tioned radially outwardly open channelsection of generally U-shape in section formed therein, said heater unitbeing secured to a center portion of said circuit means connecting tosaid thermostat and said heater unit and being connectible to a powersupply, and

metal plate in sealed engagement therewith, said base means for saidplastic container operatively semetal plate and channel section beingformed of a cured thereto.

single metal sheet, said channel section being radially 11. A smallportable electric apparatus, such as a spaced from said heater unit by acontinuous intercoifee maker, for heating liquidsincluding mediateportion of said metal plate, a substantially rigid hollow liquidreceiving body havsaid metal plate being secured to said plasticcontainer ing a substantially vertical axis, said body being of to closesaid aperture by a portion of said plastic conmolded plastic possessingresistance to the conduc- 13 tion of heat, said body having a side Wallterminating in a bottom opening,

a metal plate of greater size than said opening,

means for securing said metal plate to said body comprising aninterlocked connection between peripheral portions on said metal plateand a peripheral portion of said body surrounding said opening to sealthe opening and directly secure said metal plate to said body,

an electric heater secured to a center portion of said metal plate insealed relation thereto, said interlocked connection being radiallyspaced from said electric heater by a continuous intermediate portion ofsaid metal plate,

said electric heater being within but spacially and thermally insulatedfrom said plastic body by said continuous portion of said metal plate,said continuous portion being of an area correlated with the wattage ofsaid electric heater, the size of said metal plate and the material fromwhich it is made, and the composition of said plastic body so as toprevent the transfer of excessive heat to said plastic body therebypreventing damage to said plastic body by any use thereof; said metalplate being in contact With the liquid in said plastic body,

a thermostat positioned below said metal plate in operatively directheat exchange relation thereto to be primarily controlled by thetemperature thereof in normal operation of the appliance,

circuit means connecting to said thermostat and electric heater andbeing connectable to a power supply, and

base means for said plastic body operatively secured thereto.

12. A small portable electric apparatus, such as a coffee maker, forheating liquids including a substantially rigid hollow liquid receivingbody having a substantially vertical axis, the body being of moldedplastic and having a side wall terminating in a bottom opening,

a metal plate of greater size than said opening,

interlocking means including endless tongue and groove portions formedon a peripheral portion of said metal plate and said body surroundingthe opening to seal the opening in said body and secure said metal plateto said body, said interlocking means comprising a tongue on one of saidbody and said metal 14 plate and a groove on the other of said body andsaid metal plate,

an electric heater secured to a center portion of said metal plate insealed relation thereto, said interlocking means being radially spacedfrom said electric heater by a continuous intermediate portion of saidmetal plate,

said electric heater being within but spacially and thermally insulatedfrom said plastic body by said continuous portion of said metal plate,said continuous portion being of an area correlated with the wattage ofsaid electric heater, the size of said metal plate and the material fromwhich it is made, and the composition of said plastic body so as toprevent the transfer of excessive heat to said plastic body therebypreventing damage to said plastic body by any use thereof; said metalplate being in contact with the liquid in said plastic body,

a thermostat positioned below said metal plate and electric heater inoperatively direct heat exchange relation thereto to be primarilycontrolled by the temperatures thereof in normal operation of theappliance,

circuit means connecting to said thermostat and electric heater andbeing connectable to a power supply, and

base means for said plastic body operatively secured thereto.

References Cited in the file of this patent UNITED STATES PATENTS1,385,999 Howard Aug. 2, 1921 2,046,710 Umstott July 7, 1936 2,515,385Wales July 18, 1950 2,526,566 Kolisch Oct. 17, 1950 2,730,610 Farr etal. Jan. 10, 1956 2,753,088 Prahl July 3, 1956 2,929,908 Parker et a1.Mar. 22, 1960 3,078,785 Antonelli Feb. 26, 1963 FOREIGN PATENTS 498,928Great Britain Ian. 17, 1939 719,962 Great Britain Dec. 8, 1954 728,676Great Britain Apr. 27, 1955 864,363 Great Britain Apr. 6, 1961 1,263,031France Apr. 24, 1961

11. A SMALL PORTABLE ELECTRIC APPARATUS, SUCH AS A COFFEE MAKER, FORHEATING LIQUIDS INCLUDING A SUBSTANTIALLY RIGIDHOLLOW LIQUID RECEIVINGBODY HAVING A SUBSTANTIALLY VERTICAL AXIS, SAID BODY BEING OF MOLDEDPLASTIC POSSESSING RESISTANCE TO THE CONDUCTION OF HEAT, SAID BODYHAVING A SIDE WALL TERMINATING IN A BOTTOM OPENING, A METAL PLATE OFGREATER SIZE THAN SAID OPENING, MEANS FOR SECURING SAID METAL PLATE TOSAID BODY COMPRISING AN INTERLOCKED CONNECTION BETWEEN PERIPHERALPORTIONS ON SID METAL PLATE AND A PERIPHERAL PORTION OF SAID BODYSURROUNDING SAID OPENIG TO SEAL THE OPENING AND DIRECTLY SECURE SAIDMETAL PLATE TO SAID BODY, AN ELECTRIC HEATER SECURED TO A CENTER PORTIONOF SAID METAL PLATE INSEALED REALTION THERETO, SAID INTERLOCKEDCONNECTION BEING RADIALLY SPACED FROM SAID ELECTRIC HEATER BY ACONTINUOUS INTERMEDIATE PORTION OF SAID METAL PLATE